Reff galbraith



UNITED STATES ATENT urine.

DAVID R. SI-IIRREFF GALBRAITI'I, OF AUCKLAN D, NEV ZEALAND, ASSIG-NOR,

BY DIRECT AND MESNE ASSIGNMENTS,

OF ONE-THIRD TO SJ'XMUEL C.

MAGKY AND ARTHUR M. MYERS, 0F SAME PLACE.

METHOD OF EXTRACTING GOLD AND SILVER FROM ORES, &c.

SPECIFICATICN forming part of Letters Patent No. 553,115, dated January14, 1896.

Application filed July 20,1893. Renewed June 17, 1895. Serial No.553,153. (No specimens.)

To all wit-0m it may concern:

Be it known that 1, DAVID RANKEN SHIR- REFF GALBRAITH, a subject of theQueen of Great Britain, at present residing in Auclc land, New Zealand,have invented a new and Improved Method of Extracting Gold and Silverfrom Ores, &c., of which the following is a full, clear, and exactdescription.

The object of the invention is to provide a new and improved process forthe treatment of gold and silver ores to rapidly and economicallyextract the precious metals from the materials containing the same.

The process consists of subjecting the pulverized ore to the action ofheat and a molten alloy containing sodium or its equivalent as theactive agent.

This process is applicable to a large variety of ores containingprecious metals. The ores most suitable, however, are those in which theminimum amount of sulphur exists in metallic combinations other than theprecious metals.

Sulphides and tellurides of silver and gold are very rapidly decomposedby this method of extraction and the precious metals secured. Inapplying the method several mechanical contrivanccs may be adopted; butfor the purpose of illustration I shall adopt a revoluble cylinder madeof iron and placed horizontally and suitably supported. This cylinder islined with lire-clay bricks in the form of rings or of other suitableform admitting of easy replacement. Outside the cylinder is a coating ofasbestos or other non-conductor, and which is kept in place by means ofa sheet-iron jacket properly hooped. The cylinder may be made of anyconvenient size, to contain when one-third full from one hundred-weightto a ton of ore, and provided with suitable means of charging anddischarging. Into this cylinder I throw sufficient glowing charcoal toheat it up to the melting-point of lead, blowing in air by any suitablemeansbellows, for example. When hot enough, I then run in any desiredquantity of sodium and lead alloy. I find lead containing about threeper cent. of sodium a suitable proportion to use as a constant, addingrich sodiumlead alloy as the sodium becomes consumed by the sulphides,tellurides, chlorides, 650., of the precious metals or by other basesulphides which may unavoidably be present in the ore being treated. Theproportion of alloy to ore may be about three per cent. or more, asfound convenient or advisable. When the alloy has been run into thecylinder, the desired quantity of ore, in powder, is then introduced,(and in the case of the cylinder apparatus the ore should be red hot,) aquantity of glowing charcoal added, as may be required, and the cylindermade air-tight, a small spring-tap being provided at the axis of thecylinder to admit of the adjustment of the outside and inside pressureon the cylinder. The cylinder on being revolved upon its axis insuresthe contact of the ore and molten alloy, the sodium of the alloy unitingwith the sulphur, tellurium, &c., combined with the precious metals,thereby liberating the latter, which immediately alloy with the lead. Inan hour or so it will be found that the extraction is completed. Thecontents of the cylinder is then discharged into water, so that coolingmaybe quickly effected, when it will be found that part of the alloy isdistributed throughout the mass of ore and that particles of lead andore are here and there adhering. The whole contents of rho cylinder asdischarged is passed through rolls, which detach the lead and ore,flattening out the former. Then comes concentration, by which the leadalloy containing bullion is separated from the ore, and this, along withthe larger pieces of lead, is passed on to the next charge, if not richenough to cupel at once. XVhen the cylinder has been discharged no timeis lost in introducing another charge of ore, so that the heat may beconserved, the heat of the red-hot charge of ore being sufficient toperpetuate the working temperature.

Instead of lead, zinc might be used, if found more suitable, or an alloyof lead and zinc, or any other metal or alloy commending its adoption asan alternative. Potassium might also be used instead of sodium, if everproduced cheaply enough and found 'to be of equal working value, or anadmixture of potassium and sodium, if expedient or of working value.

Instead of charcoal, coal-gas or other suitable gas maybe used, thecylinder being provided with a tubular shaft adapted to admit such gas.I do not, however, restrict myself to any special. form of plant, butreserve the right to use any plant I may find most suitable for thepurpose of securing contact of ore with alloy in a non-oxidizingatmosphere.

Having thus described my invention, 1 claim as new and desire to secureby Letters Patent- The herein described process for the treatment ofgold and silver ores, consisting in heating the pulverized ore andsubjecting LE 10 to the action of a molten alloy containing sodium orits equivalent as the active agentsubstantially as described.

D. R. SHIRREFF GALBRAITH.

Witnesses:

JOSEPH JAMES MAcKY, SAMUEL COCHRANE MAoKY.

